MoSe₂@MoO₂hybrid nanostructures decorated with gallium nanoparticles for room temperature hydrogen gas sensor

Hydrogen (H₂), a clean and sustainable energy carrier, is crucial in global efforts toward decarbonization and environmental sustainability. However, its flammability and explosiveness at concentrations exceeding 4% necessitate precise, real-time monitoring to ensure safety in industrial and domestic applications. Conventional H₂gas sensing technologies have several limitations, such as high cost, complexity, cross-sensitivity, sensor drift, and elevated operating temperatures. To address these challenges, we fabricated a highly sensitive and selective H₂sensor using Gallium nanoparticles (Ga NPs) decorated MoSe₂@MoO₂hybrid nanostructures working at room temperature (RT). The hybrid of MoSe₂@MoO₂was grown using the chemical vapor deposition (CVD) technique, and further, the grown film was decorated with Ga NPs to enhance its sensing performance. The hybrid nanostructures exhibited an ∼11% response to H₂at 30 °C, with notable issues in recovery and selectivity. By incorporating Ga NPs with an optimized concentration of 10μl, the sensor achieved an enhanced response of ∼47% at 30 °C (i.e.4.3 times increase in sensor response) with tremendous selectivity towards NO₂, CO₂, H₂S, and NH₃gases, and the sensor shows a lower limit of detection (LOD) of 47.8 ppb. The sensor demonstrates a fast response and recovery time, exceptional durability, and prolonged stability. This improvement is attributed to the synergistic interaction between the hybrid nanostructures and the catalytic properties of Ga NPs, enabling superior response, stability, and selectivity at RT. This work illustrates a considerable improvement in semiconductor-based hydrogen sensing by proposing a robust, cost-effective, and energy-efficient solution. The proposed sensor demonstrates strong potential for next-generation gas sensing technologies, providing a portable and reliable platform for real-time hydrogen monitoring in various applications.